Speed-controlled electric switch.



T. W. SCOTT.

SPEED CONTROLLED ELECTRIC SWITCH.

APPLICATION FILED APR. 17. 19x4.

1 ,21 0,709, Patented Jan. 2, 1917.

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SPEED CONTROLLED ELECTRIC SWITCH. APPLICATION HLED APR. 17, 1914.

1,219,70Q. Patented Jan. 2, 1917.

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THOMAS W. SCOTT, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE AMERICAN TRAIN CONTROL COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

SPEED-CONTROLLED ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Jan. 2, 1917.

Application filed April 17, 1914. Serial No. 832,441.

To all whom it may concern:

Be it known that I, THOMAS W. SCOTT, a citizen of the United States, residing at Baltimore, State of Maryland, have invented certain new and useful Improvements in Speed-Controlled Electric Switches, of which the following is a specification.

This invention relates to an improved construction of speed switch and has particular reference to a switch to control an electric circuit in a speed control mechanism for railway vehicles. i

The present invention is designed especially for use in speed-control stop devices for railway vehicles, such for example as set forth in pending applications filed by me January 31st, 1914, Serial Number 820,462; and February 20th, 1914, Serial Number 821,408. In said pending applications the speed switch is shown in connection with a train control system wherein a controlling means on the vehicle is normally held against operation by an electro-magnet which latter is energized by a current from a supply on said vehicle. The roadway also has a series of ramp rails which latter during conditions of safety, have a connection with a local current supply so that a contact on the vehicle, when passing over such ramp rail, will pick up a current, and by means of the picked-up current, maintain the vehicle magnet in an energized condition. Under the said system however, if the track ahead is occupied, or conditions ahead are such as to require'caution, the connection from the local current supply to the ramp rail at the entrance to the block will be interrupted so that no current can be picked up from said ramp rail, and unless the speed of the vehicle is much reduced, an automatic stop will be effected.

The present invention therefore relates to a speed switch to be carried by the vehicle, and by means of which the vehicle will be allowed to proceed at a low speed into a block or section where caution is required,

but will operate to effect an automatic operation of the controlling means if the speed of the vehicle is in excess of what it should be when caution should be exercised. The invention is illustrated in the accompanying drawings, wherein- 4 Figure 1, shows the device in front eleva- 'ln'g inclosed by a housing.

the movable contact and its actuating stem,

and Fig. 4, illustrates a cross-sectional detail through the guides and stationary contacts, the section being taken on the line 44 of Fig. 2.

' Referring to the drawings the numeral 5, designates a casing, the interior of which has a piston chamber 6, and a pump chamber 7, which chambers are in restricted communication by means of a narrow vertical passage 8, and also by a passage 9, which extends from the bottom of thepump-chamber 7, to the bottom of the piston chamber 6, as shown in Fig. 2, of the drawing.

The pump chamber 7, contains one or more rotary heads 10, each with a series of circumferential blades 11, therein, and a shaft or stem 12, extends vertically from the rotary head 10, and on its upper end carries a worm gear 13. A horizontal shaft 14, extends across the upper side of the casing and to one side of the-worm gear 13, said shaft be- This horizontal shaft carries a worm or worms (not shown) to mesh with and drive the worm gear 13, and a pulley 15, is carried on the outer end of the shaft by which the latter is driven. In practice a belt is passed around the pulley 15, and is driven from a suitable pulley on one of the vehicle axles so, that motion to the shaft 14, is derived from the Vehicle axle.

The piston chamber 6, contains a piston 16, from which a stem 17, extends vertically and projects above the casing 5. The normal position of this piston, when the vehicle is at rest and shaft 14, is idle, is adjacent to the bottom. A fluid, such as oil, is contained in the pump chamber 7, and when the head or heads 10, are rotated, slowly or fast, accordthen passing through the restricted passage 8, and returning to the pump chamber.

The mechanism of the pump chamber, piston chamber, rotary shaft and pulley is not new per se, and is used in the same way herein described in an apparatus for recordin the speed of vehicles. By combining this part of the apparatus however in a novel way with a novel-arrangement of contacts, I am enabled to produce a speed-'' switch that is particularly well adapted in the safety train control system of my said pending applications,

A plurality of posts'18, extend vertically from the upper side of the casing and a horizontal cross-bar 19, is rigidly sustained by said posts. 'Iwo spaced apart guide members 20, also extend vertically above the casing and the upper ends thereof are suitably secured to the cross-bar 19, while the lower endsare reduced and are seated in sockets 21, by which they are held rigidly in place. These guide members are con structed of a material that is a non-conductor of electricity and their innervertical edges 22, form vertical guide surfaces for a purpose which will be presently explained.

Between the upper and lower ends, each guide member has a rigid contact plate inserted in its guide edge, the plate in one guide member being designated 23, and that in the other member denoted by the numeral 24. A binding post 25, extends from the plate 23, horizontally through its guide member while another binding post 26, extends from contact plate 24, through its guide member. These contact plates 23 and 24, are inserted in their respective guide members so that their outer surfaces will be flush with the outer vertical guide surfaces or edges 22.

The posit-ions of the guide members are such that the stem 17, of the piston 16, may have vertical movement between them as the piston is moved vertically in chamber 6. This stem 17, as shown in Fig. 3, has its upper end extending vertically between the guide members and the upper end of the stem carries a cross-head 27, with guide rollers .28, at opposite sides thereof. These rollers contact with the vertical edges 22, of the guide members and guide the crosshead as the piston stem 17, is raised or lowered. The rollers 28, are formed of fiber and are non-conductors of an electric current.

A metal. head 29, is secured on the upper side of the cross-head and said head has two upwardly extending contact arms 30 and 31, respectively which press or rub againstthe guide edges 22, as the crosshead and stem are moved vertically. By

this means when the stem is raised as the speed of the vehicle is increased the contact arms 30 and 31, will move upwardly along the guide edges and when a predetermined speed, say ten miles per hour, is reached the ends of these contact arms will pass onto the insert or contact plates 23 and 24, and

vwhile on the same will close a circuit or y and complete a circuit therethrough. Upon a further increase of speed the stem 17 will continue to rise and arms 30 and 31 will move upwardly and pass from said contacts 23 and 24, thereby again breaking or opening the circuit.

In order to return the stem and its atmovable contacts to the lowered position which is below the stationary contacts 23 and 24.

In practical operation the switch is designed to open the circuit across contacts 23 and 24, when the vehicle is at rest, but when moving at a speed of ten miles per hour or under, to close a circuit between said contacts and when traveling at a speed above ten miles per hour to again open the circuit between said contacts, as fully ex- 1j plained in the pending applications hereinb'efore referred to.

Having thus described the invention what 7 I claim 1s,

1. In a speed controlled electric switch for railway vehicles the combination with two vertical guide members spaced with respect to each other and having guide edges ofinsulating material, of a stem movable vertically between the insulating guidem;

edges; a contact plate embedded in each guide member and having its outer surface flush with the insulating guide edges of the spaced guide members andacontact device carried by and movable vertically with the stem and extending across the space between the guide members said contact device serving to simultaneously make contact. with the plates in each guide member.

2. In a speed controlled electric switch I-T- for railway vehicles the combination with two vertical guide members spaced with respect to each other and having guide edges of insulating material, of a stem movable vertically between the insulating guide edges; a cross-head carried by the stem and having rollers to engage the spaced guide edges of the guide members; a contact de- In testimony whereof I afiix my signature vice also carried by the stem and having in presence of two Witnesses. yielding contact with said guide edges; 0011- THOMAS W. SCOTT. tact plates embedded in and flush with the Witnesses:

5 guide edges of said members and means for LOUIS C. KLERLEIN,

operating the stem. CHARLES B. MANN, Jr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. G. 

